import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);

        double n = sc.nextInt();
        double g = sc.nextInt();
        double v = sc.nextInt();
        
        int k = (int)n/5;
        double m = (k*g)/v ;
        
        System.out.println(m);  
    }
}